A context for the last Neandertals of interior Iberia: Los Casares cave revisited

Abstract

Introduction and objectivesAlthough the Iberian Peninsula is a key area for understanding the Middle to Upper Paleolithic transition and the demise of the Neandertals, valuable evidence for these debates remains scarce and problematic in its interior regions. Sparse data supporting a late Neandertal persistence in the Iberian interior have been recently refuted and hence new evidence is needed to build new models on the timing and causes of Neandertal disappearance in inland Iberia and the whole peninsula. In this study we provide new evidence from Los Casares, a cave located in the highlands of the Spanish Meseta, where a Neandertal-associated Middle Paleolithic site was discovered and first excavated in the 1960’s. Our main objective is twofold: (1) provide an updated geoarcheological, paleoenvironmental and chronological framework for this site, and (2) discuss obtained results in the context of the time and nature of the last Neandertal presence in Iberia.MethodsWe conducted new fieldwork in an interior chamber of Los Casares cave named ‘Seno A’. Our methods included micromorphology, sedimentology, radiocarbon dating, Uranium/Thorium dating, palinology, microfaunal analysis, anthracology, phytolith analysis, archeozoology and lithic technology. Here we present results on site formation processes, paleoenvironment and the chronological setting of the Neandertal occupation at Los Casares cave-Seno A.Results and discussionThe sediment sequence reveals a mostly in situ archeological deposit containing evidence of both Neandertal activity and carnivore action in level c, dated to 44,899–42,175 calendar years ago. This occupation occurred during a warm and humid interval of Marine Isotopic Stage 3, probably correlating with Greenland Interstadial 11, representing one of the latest occurrences of Neandertals in the Iberian interior. However, overlying layer b records a deterioration of local environments, thus providing a plausible explanation for the abandonment of the site, and perhaps for the total disappearance of Neandertals of the highlands of inland Iberia during subsequent Greenland Stadials 11 or 10, or even Heinrich Stadial 4. Since layer b provided very few signs of human activity and no reliable chronometric results, and given the scarce chronostratigrapic evidence recorded so far for this period in interior Iberia, this can only be taken as a working hypothesis to be tested with future research. Meanwhile, 42,000 calendar years ago remains the most plausible date for the abandonment of interior Iberia by Neandertals, possibly due to climate deterioration. Currently, a later survival of this human species in Iberia is limited to the southern coasts.

The early Aurignacian dispersal of modern humans into westernmost Eurasia

“…The number of “late” Neanderthal sites (<42 ka cal BP) has diminished substantially since the application of new dating techniques showed them to be much older (>42 ka cal BP) than previously thought ( 30 – 33 ). Across central Spain, there are no Neanderthal remains or Middle Paleolithic sites dated after 42 ka cal BP ( 34 – 36 ). At present, Gruta da Oliveira, Cueva Antón, and Gorham’s Cave remain the only “late” Neanderthal sites in southern Iberia dated ∼37 ka cal BP or later ( 21 , 22 ).…”

Timing of the Middle-to-Upper Palaeolithic transition in the Iberian inland (Cardina-Salto do Boi, Côa Valley, Portugal)

“…New data for the timing of the Middle-to-Upper Palaeolithic transition in Iberia Different models have been proposed for the timing and nature of the Middle-to-Upper Palaeolithic transition in Iberia, based on radiometric dating of archaeological layers and lithic assemblage technology. The reevaluation of the stratigraphical contexts and the application of new dating procedures have led some authors to consider that Neanderthal populations did not survive much longer in the Iberian Peninsula than in the rest of Europe (Maroto et al, 2012;Wood et al, 2013;Higham, et al, 2014;Alcaraz-Castaño et al, 2017). Based on luminescence dating of loess deposits from the Upper Tagus Basin, it has been suggested that the abandonment of the interior of Iberia by Neanderthals occurred 42 ka ago, and that, as a direct consequence of a pronounced environmental aridity, inner territories were uninhabited until 28 or 25.5 ka.…”

New data concerning Neanderthal occupation in the Iberian System: First results from the late Pleistocene (MIS 3) Aguilón P5 cave site (NE Iberia)

“…Archaeological sites in caves or rock shelters are located from 700 to 1280 masl over riverbeds or ravines, passages between valleys and plateaus or places where there is a broad visual domain or that form a sort of natural trap. Some of them have been interpreted as being sites of extended or repeated stays, such as La Ermita and Cueva Millán (Moure and García-Soto, 1982;Díez et al, 2008), Peña Miel (Utrilla et al, 1987), Los Casares (Barandiarán, 1973;Alcaraz-Castaño et al, 2017) and La Quebrada (Villaverde et al, 2017). They reveal more or less structured hearths and anthropic fractures in bones that accompany the recovered lithic assemblages.…”

“…The abandonment of these territories, apparently independent of the arrival of first modern humans, is linked with the onset of hostile climatic conditions characterized by the driest conditions of the last glacial period (except an even drier period linked to H3) that precedes the onset of H4. No archaeological or palaeoanthropological evidence attests to a Neanderthal presence in the whole interior of Iberia since 42 ka ago (Alcaraz-Castaño et al, 2017;Wolf et al, 2018).…”